SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '532d1056a9aa59312622a800ac83e1245ee943dfcf122b320476df9bfb9d273c' 
  AND token = 'RzfAwtaAT/kayjrBlWyTVpa3uQh6Lkbh1KNu1q+NHCg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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