SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e00bccc1f84250c6d9f5d18f5d983ad50f7e43fd1c561f2ced1835d4bfae6c3' 
  AND token = 'eV0qan4JA88IY78QqPkHsDYdG9G458hnBfkwAt9erhQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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