SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f4f296b7e6ed2adba41e83736b01a4c33c648826ef740bf88dd1d045f656e79' 
  AND token = 'p9rF7PwG3j8LxQxzv4/FXdV7mLlusWHvBn06ryp3IZU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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