SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '204b1bcbb7d2d1379505fa0839737c7ae87a8034e11ad4adc3e285f884672377' 
  AND token = 'SXbQEDD71wzjUqz9XReBdTpZaqK2OMNnvMrbBReBazw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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