SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c28477600fc496adb59cd9de7884d8e4af9bb89ba0467eb14d5c230c3e23fd8' 
  AND token = 'QFFHmRp6cVYyFDPqx+ryFJsvCEphmZ7/FWH0V7w3ly4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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