SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c07576799afdc1dc50eeaa1947478a2dcf55d24221748f36a1401e17c01c5ae8' 
  AND token = 'ZTbXdNGo+uULPNWl9s5Quqt5Rcfk6JOpe6aUiaEESmQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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