SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '677b1f04e3d094d53285c059e4e0c3fcc499c2ff78efbdbe1b747f4f3d9ea198' 
  AND token = '2YJzGMeXxlhmZl2R5yA1OqBB6bUHAVt9QTpXTg5ZB7k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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