SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e79229d53cdb58c593bd1fa750b5c21c66d7bf3af2aaff78c5e0f148f9e5ce7' 
  AND token = 'pYDG9qVLLBkB4FvBtzWDnvjZkq4epVSJTBvsFhNkcFA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00076

JSON explain

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