SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '64ef8883a1623bf477770d5d84d63daff1cc9c2589d9c3c0d537bbc15aaab9f2' 
  AND token = 'AK68DM9nWt+7GjPOyfPRpKy5vtSTg6KCa+gEenH27vM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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