SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0c8225b3a045443ff21bfaf64fa3157d34a7a1727047cbb15d1b1d146e4427e7' 
  AND token = 'QhQcJkwddFVCvPU73nLsRumwFVGxDhy2VzGZn7gSv4A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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