SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ed4410afe5afbf8ae188eda321bdc380342dfd517b3f2c448dab56eff8586c71' 
  AND token = 'U+dS1V7uL1iQMh2qScBjjsXsNXEPsqHEMYjsLbqPuxQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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