SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a4d495b42162c42e3abc6cbe1e442a39a8e5774a34c5899144e6f1bb45e578b' 
  AND token = 'utcZBigcCb0lGahuKmM+B9/MZu9N2Vj1Qt/2/yCIf8Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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