SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b34e8c12e2023577fec7f9e1cc46daf36566260906fcd36c61a20db23fa32f7f' 
  AND token = 'JskHmE+0HLBqnXEpcsKtCHFfpNRju96UiDgpZ2vBpzs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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