SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '61249419b6269852d719354764afb2740b4a5d2fb8ed9323c3eba447983fc995' 
  AND token = 'OzRnAwKTmkoEIdEy9HKJlly8stZW7EKrlkfJDOdrMxc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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