SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a7f46cd11fb696c31d3da8034f5b4e9ff82418b02b995e7413207cf59142c479' 
  AND token = 'M/IG/CUiNhq0xV8x6/24SMb25BbNeTKznXKLLXZC9Ys=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}