SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fde794f82d19a094235c7d6c3bee5afbc0a818d2f212f5da95c11aff56e6120a' 
  AND token = 'DEScWGsDFvmVFViDf2c5+7yW/g8WlLO2WSDPjmrCobw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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