SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b4f6133b2de43b6df426d52d53c67ba2cb5ba3606fba1d1fc8e87d79dc1c1b8e' 
  AND token = '+M7DIDqaBVs6YwkgZWvkkLECpYNyAdUmgDCh3mG0LUY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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