SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2b51b0e6129bf204a1ba657a099586c0670040eb16bbb6b0c29ea556cebe4ec8' 
  AND token = 'NLRd5k5craX/f2zmxdChvkjv1lsGtkiGVAw6O53tlSQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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