SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6415a536fa2c7a140eb8e562bb149e51b1094b369beefb024e2830708599e3dc' 
  AND token = 'W7V9/CqQsITnSVxf0vjLH3WgotuEolH/1gNj4T7qUPw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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