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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd58bbc4c2d6d1ab6ea6122879ab7197716aa2d87dd5f55f3314478988286a91c' 
  AND token = 'j3/VHfMu+rHR6u0CTmJuQO9Ki3DRu7vfJVQoLPKakjk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

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