SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '599fecc18977727aec6a7ca3f1ac264778c2bd760814a3fdaa2978b86052e9f9' 
  AND token = 'VH3cybsuvQwN6rvQ7ZRencrpHIEQDERr9U4QjixwUjk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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