SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cb50b73fdb2054164aaf24c9572408568da0d996c9cd1d91af99aabddb9a30fb' 
  AND token = 'eNZDoSXoWll0omo264aw3i5JgXzpeceY3KURXk+Xp9o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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