SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eb8c4cdfd1b2653ecdf811cf5d5e3688c865a6c04f29d02b98f306cae6015802' 
  AND token = 'dsm3lGpQEljBDooLzBpePegRNzDZhCTO4AtyLED36aA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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