SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c8f8b24831f196179d55fb5d3821402419ec33cc527a1d106e7446c9280a06a7' 
  AND token = '9YEOP6GYR4ZNSxxXPfBfXrcybKUotSM+N2R7FcWrsX0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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