SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '836d8292ec410862b80750d42c42ddb40aa5e7308fd098a4be56ec8ef20eb8a0' 
  AND token = 'DwlcdzN1Ss6pa2S1IIDDHfZYgukRuDHDX8nPY1xyNc8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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