SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c0e842c5563a75c5349d9b01ed69bd21616d1ca40aed90642275757431aae87' 
  AND token = '1z6uRAx+ZKX4RjyJF/+lMnQP25qDKUuNwH//qgHvFTI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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