SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ad6ae4f996a88ffc21a06ecc5960d447e38029ebac850af5916281918e672c3' 
  AND token = 'Cgnuxr0eIAgYzFMkPLJ/xIGklFef5JvadpzUDeePe+M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}