SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57cf47eb22f6fdf377e8687a16693daa8e66ac87112d6b40ee725505f808c396' 
  AND token = 'ui+qo23/gVbDPA0ErUPmTRWhejSOXiPgpbvXZFiF98w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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