SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'efec671d70e79d738342ed9082dd2037e572a54bc8bf0eea4addc02ea45ddcb9' 
  AND token = 'QxpJkefOAGZ0AEc/oXgssNAB4xal3YSMdjErSmN3Y2Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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