SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c182d958e201707038e14ede6d8345cee150f43f73c055c1eaadf3cacbf82e1f' 
  AND token = 'ntrNIcUOuSbqk5VKv9RKEIyt/Y+hYlaKzSHE8ehEffQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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