SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0f43ec1894cc407176cb8268a13da976803e13efdb4a915978fd93795460c5c3' 
  AND token = 'wVDV+IT0cZBv4ulyga1xUdHYxe4KZY1SlLOF5dDFc1E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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