SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a8e159f51a5cacb08e238ef2744a34dd98a164a5bae7dafd2f2d373ad64bde3' 
  AND token = 'mnvMU9gyrWpa0/3LZg+eyoWZkfDMm8rAVL4YPpbZazo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}