SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4db1d349065267609d28320f35e398828758a6c0053f227de936f0c396031ba1' 
  AND token = 'G7gFfOmJkoEvTa5Gzx3h3+pJl8c5ppxRmY0EdOAIjqI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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