SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '830ec883327b03d73afee4147b37e8c51b8bc72ef231fc6979cd8b6f0b942525' 
  AND token = 'fCZzPGBfYvWxj2R/ai0CCrJac/SJos3yMfgsDcnb7xw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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