SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '47452812b89267078a2e0134f4a9476d17529b8ffba63cd317eb4dc706b38ef2' 
  AND token = 'fc6pEoWMY/9JcWRtHZOFU22mnNXlCWQcq9/Yhi+/VKw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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