SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e31eb0dd066eec4221188d9d28c197a21e5bfd8d73018f3fc2847bdd36a36539' 
  AND token = 'U2GRPoFUreEPfz00yfRkBSUjweL8CrS+sfse5zqzbk8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

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