SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '509ad95133217d72c8ea17f5cad4ba4eef3b17ed5b31c05060a053c816849be8' 
  AND token = 'zOEjgjk7HhMWGvOCCBCwlR8m62FBQlZ+yIZg0FfS0oE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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