SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5dc0d84018759b701de63223af4d0fe6351249b48ee79b6c813d8f6e1f6844e7' 
  AND token = 'ChufutTmJpKhfK3LeFGGHDS+i8NX+0CLd/HVznPqnwk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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