SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b3db21b40b916eb6337bf7e1153b998acbb98079091ed9ba37b16ff6b66bc3a' 
  AND token = 'oHfhaz3u4YiAMbOQJqDIoARLYY5JPrk6FDe78upkegk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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