SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '54dda61d730f073e57aa6ea3ac84cf2c613fac130cab99e210f1ea472d5b3591' 
  AND token = 'gGTsmKUvMbP+qkcrmDLfAxTkjDvTa0rVeIuMiUf/0X8=' 
  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"
    }
  }
}