SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b5fb3c616854f3215e493d02234df4170dd9670f052bdb1deae935ddaaf4c8f1' 
  AND token = 'QyfQ+WEUPQRuTYv2S0u0inQ9jA8Jt02kTaO/wjTmjnc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00063

JSON explain

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