SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2157f5562434e63a15ce86e57576b6b8a51db664fab88ff06d650380a7ad0a27' 
  AND token = '7mL2VlFNGaf4zDwOlUgU9+HxHFqIcP+AQfrY6dgzfsY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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