SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd5d132775b912f1be43e96b505679833ed9d53e626cdfc9d466adfa306a1dc1' 
  AND token = '8/8ogI5DQ7cGhTed81irPG3PmGbXXWlpl1bWudeOWME=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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