SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f76b8979d023f0cd1c6ac8b4f09ded33bbdf2c71a2cb678fb1a866dc3ff79e5d' 
  AND token = 'sWnqI56nEqu86rk/sqwfHChe/Wq/h7Uzd0IuqGdihq4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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