SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c3a565c457e2260b87da716eb2cb05d2c094923c95046d7cfe62bd1bf02d0ae' 
  AND token = 'SDqZSzp42GPANM6jNeTBYyX+a3FGbfSs/4lk4uQFEAc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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