SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff6e5eded375b4ccf1e3dd14a3dab7143bf1e9190b4da8a6e2d84d3fe0765fd5' 
  AND token = 'XEmWDK/SVyGiaqyy7ZgV8DUIqNrdHJenfJFaf9LcTog=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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