SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '73c04f5ef0a598be237511b2b4f7cb8ef264caf83e2b8b1b0773766998685a13' 
  AND token = 'DsIijXMOVLiWiE93LXMaejfo1dkc/utY0fT0OkPoKvA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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