SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a19c4a91a2d67a2f4453f33be4841818d2c964a813efec7992b4609f8ae30b5c' 
  AND token = 'Lcx9thg6XhD6hCup6eZPpR2dhpj+OWdG6H1Jbv70OXM=' 
  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