SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '353cc46f8d884efb8f8a079884751317c861c3f1b0f5e0ade4449895e92ce5db' 
  AND token = '14fUxY+bkm6aLLKA0w9Vcsdt6ZUCc9ZXZ2vZwcdqbHM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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