SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '819bf5deba2c3f0ffff60a3998787b788dd6f38fd758cfb701dd688a69919aff' 
  AND token = 'UENKU37TogvZ3D6uqyuCQlRs4ifO2jsUQWR/4BhqX08=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

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