SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0db3c7fcf27a12215a7495f33106a7a0fc699fc80ef0a75a0365d257db60c141' 
  AND token = '4tW6goywy2yd2Wq2EqqnoO0JF0ERMyansLbIQx0uPx4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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