SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '713a34302557b7021975d7b09fea6f22ff1b5ab44629b71f368d67933a7a0daa' 
  AND token = 'tdGJAkL5XerYzXYqGC83myJS0/LeDyeYf0kKDDV/t2w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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