SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8bea6b994975063eaf718228baf13e02b0266047f936cf287b2d1734878b20dd' 
  AND token = 'gYqsI4+rDh+pqArZl1zA0Z5rfiPPaISuV0kEm47TvGA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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