SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5008fb91fb812c73a1676c5bba6254ab178a4000df313bb7d0d24c5bb5eea10a' 
  AND token = 'sJeikRzevdlEg5OFFdIxnXCSAmjfWyL768CFjIqVcAA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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