SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c60fcadcb42b7c7400848d734039b064168945aff7be6a34ce478e98a4e2d8a' 
  AND token = '+fpAbE60PDoJgqQdpjh77NCOEpeosPoB4xJHJgxnHhA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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