SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2df2ea9e11545bc2670821937a3d68352d068d4899028ea7d070e26e6b2f8047' 
  AND token = 'oPnvj2PxY6WUTtUm/vc8oTf3wT0dIp13J5RMbsamw+I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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