SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd5c2f78f8e276bc167347428cba86e2a3dcf9a1d3db83ac053289f9de34d9367' 
  AND token = 'B25GXk0N8WJcGq+FKdYCcFm1vBQi3Gfnj3IqjBLRDlU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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