SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f932ba31fe609f2e69e3ce3ab8fbedec3503122e5742c43721147256c5c4c0a0' 
  AND token = 'MKHmkPKwtmpPI7payMLw/uLSS7KQ1PtiYMF+bcKRo6Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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