SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38a1242c8ebbf5b2db8c4a65de7c9710a969f14d20759f01134fbeba73445c92' 
  AND token = '2XV17Q124XwSRn4I2JyKnzUEpFyow6JYDjaOy8YWQ9A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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