SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f5cfe6d49a9f2365bddaba02dbe53afa635b5147837645c68c9ff409ece7c61' 
  AND token = '6J12AjBE49Lr8xT0oGw69YofqNu93MFxFQO5OQ7gd7c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00064

JSON explain

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