SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35679c8dd5892c4b70c348496906fd81ac1c2e83797fab0911f8247e21168792' 
  AND token = 'L5aUfb5CDLKraRmuIa2hVOANhqRpx/NuyvGbhW3ytv8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}