SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '944036726bb607c5f0aa49b52e6ce6108d613c7dc0000d5ace3ad31f4e702992' 
  AND token = 'y3GcnvttFXeYBo3Cw2MKQ3NP58jDmnJNoR9bUfWgHt0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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