SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52697ced3285d472651609e198f0f5c091a3ccf4b2d488262a53299ad131fec1' 
  AND token = 'NEAFioKdFepGUPDb4z9bmJshn+yAWQKHOgtGjI445TA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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