SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8788862a6d5caa23af6debf6a4f849be0749b030d5bfb57f11ab81911ce30ddd' 
  AND token = 'u8pxFpMP4zncFYC70qrlZYLwhg6UzHjf2UnwQ7sqmvM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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