SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '67928eeacb319e26535d19a373567f2d9bd818d823ca55d4a70cdacd07e00917' 
  AND token = 'ZzPZkuJMhg+J+YVFR8DSHwerUEFsRTSFYQ64kcmFGyU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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