SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3e9499ee1db38ce19f7916a2ecfcfc754c34256fa8cb169800e071a7be57c21a' 
  AND token = '0X24b4+iUsdWA/jtH3ZYS8qQ0/RnEqnBiKreOxmlBxo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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