SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a3f37ba985d035b57c96ca9daf713014dc495a43c7193635c1460355a3670ed' 
  AND token = 'as1KQhkiGJ5KZtT0/LT8LYDCu0C4fwvbUvQXnRStq1c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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