SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a5ecf07dd329351f72ef5e49a152a208422c7df2de1b9164ccd0160ad688c44' 
  AND token = 'SyWFhT1YihwEpVNkU4Zbg7FCuIYArBi8o0mptULqXQE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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