SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b3c43f1b15382147a24bab5b1d47643627b044c5b96502f4b822d9fbcfcef62d' 
  AND token = '1wqjmSjnE8kOBdPeP2TRCOJlESjQytV+j48ze+jewws=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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