SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0ff9ff9c30e02aaf944be8c479e7ec4c5d692644e63550ec60c8d4b1336f2810' 
  AND token = '+2APdHmCVsf1ICpzNneqDUx2C62AqjuIemX0mwwqP64=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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