SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f38f6121c7328e73698323cba55f318b4e6c5488517e277e62ce9375179943e0' 
  AND token = '40JZ8X1764dHR1a2QFkkp2Wd6tPCOFrswwe9vnaxD08=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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