SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b4549ccc2cd575e550aaac21f15e632b9f1641f20bd035185bb6097a8af9f40' 
  AND token = 'STkGj1M3GLvRzMgDwRvz12VickB/seoRgvLpFVQx7/0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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