SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '73e00ba6473cf704dab085cfc476783566e48cdd13ab98fc1fab5d33ad7362d1' 
  AND token = '+zqAaukeIAtk9awHiV9KYI4b65SpY4rBg34MoxJMVCM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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