SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cda5312c0c85065bb3bd5e917a97f214d7e35a3ea39ddfe62fc2562d8bfdec26' 
  AND token = '1ChMV55HlHXKoG+XFCzRNHNRh4L77+FnCHyQEDTLxBQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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