SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bece5021fd5533d7e9b36f370a94a7e247980cf79b975dcc9534606bef7b90b9' 
  AND token = 'TFR3KstrHwxMkz4XVIx53RsKQVU4PR3I+Jp9IC3Dblg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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