SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f2a4315cce5d8a33a7fab9dd993bd9cc6758e5659d6a44feca17904a73d4feb' 
  AND token = 'hGvuSI2XjPBvuiJ7nYAmHIlg2oFp6y9Rto6J6OqdP2c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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