SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1f27642956db0461ea39f8652644ea4534c0daf7b6adcfbce8b975be943e761d' 
  AND token = 'EBBJzz15Yf9LOoSlX4EeCZc8lfRK0kLCK4C+q8pKORM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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