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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '793a0d75900e6e09a3fc888a3dc76be2a7f91fbdc418103158f1bc31f6d64b14' 
  AND token = 'oAvDNFCFOcldwY61bsl2ZBM3YJyL4MyNyyA5xEYBOrk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00011

Explain
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE								Impossible WHERE noticed after reading const tables