SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '41e043fbe8fb1171494a5336192611b343031c205748adb8c68327ce7d27870c' 
  AND token = 'xBvPsJ0T3WAO6uKsIZeHqtJjnUOkt+rzg8XlXoMkNhY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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