SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bcf3ec5f36d0a8399b1d523eb02ba0608159b163cd50da3a7caebc8edc10d0f0' 
  AND token = 'v9Y8muQDrDZPCVTiBcsMwtrJNDJZ+hiNYop1XfFDiUo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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