SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '457fa05d3aa48d22467171c9abecf2d6351420c3749de0fa795474d30ba70fac' 
  AND token = 'QPp7ofjPmzjeyDihlbZM+1Ov0MxNcIg3vBPqXczpIKA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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