SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f54c9b50ce23818ab69eec65d64f63970147d8313be56ad47e5e7b6612c3d751' 
  AND token = 'ztasY96bYTnm7zFtllQu/ZvIro+PBn5Acp9gxjrNJT8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00078

JSON explain

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