SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd3df2267f9ae7bc0d77e307085e621c29861c511b8c29f66fb584cf00071bc2d' 
  AND token = 'o57QR0CAlEpLL/+I/iJ6Dg0KthgFBgpGetwAgZWnYvE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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