SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0e7ca9bc601e714c793413dd33c5a938c326b2ad0d383f4b90def27921f8ff34' 
  AND token = '6P1hrwJRZVZZz7EiwlrjgWkniH9Mub+tmAQJYaiyans=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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