SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd1af7e57964a34f8c250f688870950cd801fcd1dbe131c9568ad191074bdce40' 
  AND token = 'hjLheVZWIMrKA2DEXVudj9b/lW6KN9irznthAqYUDGs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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